Why 2.5 and 5 Gbps are the Next Ethernet Speeds

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For most of the history of networking, bandwidth and data transmission speeds have steadily trended upwards, from 10 Mbps to 100 Mbps, then up to 1 Gbps and 10 Gbps. At the top end, 100 Gbps for carrier transport is now increasingly the norm.

Yet despite that upward trajectory of bandwidth standards, in 2014, for the first time in history, there has been downward pressure too. First there was the 25 GbE Consortium in July. This week the NBASE-T Alliance emerged, looking to build standards for 2.5 Gbps and 5 Gbps.

The NBASE-T Alliance boasts the participation of Cisco, Aquantia, Freescale and Xilinx. As to why there is a need for slower networking speeds, it all has to do with challenges that face organizations for 10 Gigabit Ethernet deployments.

Chris Spain, Cisco VP of product management, Enterprise Networking, explained to Enterprise Networking Planet that there is an increasing need for bandwidth greater than 1 Gbps. That need in part is being driven by increasing adoption of the IEEE 802.11ac WiFi standard.

That said, Spain noted that for wired infrastructure, the existing cable is predominantly Category 5e. 10 Gigabit Ethernet is not something that can be deployed over Cat 5e cables.

"NBASE-T technology is designed for the deployment of 2.5GbE and 5GbE data rates over existing Cat 5e and Cat 6 cables sans the expensive and disruptive upgrades to cabling infrastructure," Spain said.

The new intermediate rates of 2.5 Gbps and 5 Gbps will work with Category 5e and Category 6 cables up to 100 meters span.

"It is estimated that a majority of existing cables connecting wireless access points to access switches are Category 5e," Spain said. "Therefore, this means that these rates would work with most of the existing cabling infrastructure."

Spain commented that today, 10 GbE is more prevalent in data center networks and campus backbone. He added that as 10 GbE technology matures, it will also be seen as an access technology.

"Challenges today comprise of cost and power requirements for connecting devices like APs to access switches,"

The new NBASE-T is now working towards addressing the industry’s need for supporting higher speeds on existing cabling infrastructure.

"The goal is to have the industry converge on one specification, and work with standards bodies like the IEEE for standardization," Spain said. "The alliance will also focus on expanding its membership."

Sean Michael Kerner is a senior editor at Enterprise Networking Planet and InternetNews.com. Follow him on Twitter @TechJournalist.